DE3428985C2 - - Google Patents

Description

The invention relates to a method for producing high molecular weight, optionally branched polyarylene sulfides from alkali sulfide and halogen aromatics, in which in a polar solvent, such as an N-alkyl lactum, the 0.5 to 100 mol%, based on the moles of dihaloaromatic contains a lactam, the implementation is carried out.

Polyarylene sulfides and their preparation are known (see for example US-PS 25 13 188, 31 17 620, 33 54 129, 35 24 835, 37 90 536, 38 39 301, 40 48 259, 40 38 260, 40 38 261, 40 38 262, 40 56 515, 40 60 520, 40 64 114, 41 16 947, 42 82 347, DE-AS 24 53 485, 24 53 749, DE-OS 26 23 362, 26 23 363, 26 23 333, 29 30 797, 29 30 710, 30 19 732, 30 30 488.

A number of these publications describe the addition of inorganic or organic salts in the manufacture, the lower the melt flow in the polymer or an increase in the melt viscosity of the to effect obtained polyphenylene sulfides. Only at; only when  sufficiently high melt viscosity can polyphenylene sulfides thermoplastic, e.g. B. injection molded parts, foils and fibers are processed. Without adding the above Salts are obtained from polyphenylene sulfides, which have the necessary low melt flow only through a separate and additional post-condensation or curing (curing) receive.

As salts were in the above. Publications e.g. B. used Alkali carboxylates (DE-AS 24 53 749), lithium halides or alkali carboxylates (DE-OS 26 23 362), lithium chloride or lithium carboxylate (DE-OS 26 23 363), alkali carbonates in combination with alkali carboxylates (US-PS 40 38 259), lithium acetate (DE-OS 26 23 333), trialkali phosphates (DE-OS 29 30 710), trialkali phosphonates (DE-OS 29 30 797), alkali fluorides (DE-OS 30 19 732), Alkali sulfonates (US-PS 40 38 260), lithium carbonate and Lithium borate (U.S. Patent 40 38 518).

DE-OS 31 20 538 also describes that Polyarylene sulfides with high melt viscosities by adding obtained from N, N-dialkylcarboxamides.

The use of polar solvents for manufacturing of polyarylene sulfides is known and in the o. g. Publications described.

Lactams are also mentioned as solvents. It will but when using lactams as solvents, such as B. pyrrolidone and ε-caprolactam, and p-polyphenylene sulfides with unsatisfactory properties, d. H. melt flow too high or melt viscosity too low  get that not thermoplastic without thermal post-curing can be processed.

It has now been found that in the presence of small amounts Lactam in the reaction mixture with polyarylene sulfides high melt viscosities are obtained directly without a separate thermal post-curing or a Curing can be processed thermoplastic.

Compared to the known process, the pure N-alkyl lactams use as a solvent, the Process according to the invention Products with higher melt viscosities obtained when the reaction according to the invention in a polar solvent, particularly preferably a N-alkyllactam, which is 0.5 to 50 mol%, preferably 0.5 to 25 mol%, based on the moles of dihaloaromatic, contains a lactam.

It is known that the addition of polyhaloaromatic compounds, especially trihalo aromatics as branching agents Melt viscosity of the polyarylene sulfides increased.

According to the method of the invention, polyarylene sulfides with high melt viscosities without the use of Polyhalogen aromatics can be obtained.

The invention thus relates to a method for the production of optionally branched polyarylene sulfides out

• a) 50-100 mol% of dihaloaromatic compounds of the formula and 0-50 mol% of dihaloaromatic compounds of the formula in which
  X stands for halogen meta or para to each other and
  R¹ is the same or different and can be hydrogen, C₁-C₄-alkyl, C₅-C₁₀-cycloalkyl, C₆-C₁₀-alkyl, C₇-C₁₉-alkylaryl, C₇-C₁₉-arylalkyl, where two mutually ortho radicals R¹ to an aromatic or heterocyclic with up to the three heteroatoms N, O, S containing ring and can always be a radical R¹ is different from hydrogen and
• b) 0 to 5 mol%, preferably 0.1 to 2.5 mol%, based on the sum of the dihaloaromatic compounds of the formula I and II, of a tri or tetrahaloaromatic compound of the formula ArX _n (III) where
  Ar is an aromatic or heterocyclic radical,
  X represents halogen such as chlorine or bromine and
  n stands for the number 3 or 4 and
• c) alkali sulfides, preferably sodium or potassium sulfide or their mixture, preferably in the form of their Hydrates or aqueous mixtures if necessary together with alkali hydroxides such as sodium and potassium hydroxide, where the molar ratio of (a + b): c are in the range of 0.75: 1 to 1.25: 1 can,
• d) if appropriate in the presence of known catalysts, e.g. B. alkali carboxylates, alkali phosphates, Alkali phosphonates, alkali fluorides, alkali alkyl sulfonates or N, N-dialkylcarboxamides (DE-OS 31 90 538), which is characterized in that the Reaction in a polar solvent, especially preferably an N-alkyllactam containing 0.5 to 50 mol%, preferably 0.5 to 25 mol%, based on the moles Contains dihaloaromatic of a lactam becomes.

The reaction time can be up to 24 hours, preferably 2 to 18 hours. The implementation temperatures are 150 ° C to 280 ° C.

The reaction can be carried out in different ways:
The alkali sulfides are preferably used in the form of their hydrates and aqueous mixtures or aqueous solutions. The dehydration can take place partially or completely, with either the alkali sulfide being dewatered in a preceding step without the presence of the di- and / or polyhaloaromatic compounds together with the organic solvent and the lactam, optionally using an azeotroping agent or water tractor. The entire reaction mixture can also be dewatered in such a way that the di- and polyhaloaromatic compounds are used as azeotroping agents.

If only partial drainage is used, work should be done under pressure to the necessary reaction temperatures to reach. The alkali sulfides can be used separately dried by applying water and vacuum and be added to the reaction mixture. The pressure can depending on the nitrogen pressure up to 100 bar, in generally 2 to 20 bar.

Is completely drained, which is preferably in the presence all reactants and with the di- and polyhaloaromatic is carried out as a water tractor, so pressure-free or low-pressure up to about 3 bar. To achieve higher reaction temperatures about the boiling point of the solvent or mixture from solvents and di- and polyhaloaromatic compounds higher pressure up to 50 bar can be used.

Is preferred for the method according to the invention the complete dewatering of all water-containing reactants recommended.  

The addition of the reactants can be done in several ways respectively.

All reaction partners can be put together directly be, or preferably a continuous addition one or more reactants are carried out, while drainage is carried out at the same time can be. In this way, the course of the reaction controlled and the residence time of the water in the reaction mixture be kept low.

In comparison z. B. to the method of DE-OS 32 43 185 where the water is also removed from the reaction, become lighter in color by the process according to the invention and more impact resistant polyarylene sulfides obtained in Melt fewer gases and thus fewer are corrosive.

The processing of the reaction mixture and the isolation the polyarylene sulfides can be carried out in a known manner.

The polyarylene sulfide can be obtained directly from the reaction solution or only z. B. after adding water and / or diluted Acids or organic solvents with less Solubility for polyarylene sulfides by conventional procedures are separated, for example by Filtration or by centrifugation. After the separation of polyarylene sulfide generally includes one Wash with water. A wash or extraction with  other washing liquids that are also added or can be carried out after this washing, is possible, too.

The polyarylene sulfide can also be distilled off, for example of the solvent and a subsequent one Linen can be obtained as described above.

As alkali sulfides such. B. sodium and potassium sulfide suitable. The alkali sulfides can also from H₂S and the alkali metal hydroxides or from the hydrogen sulfides and alkali hydroxides can be obtained.

Depending on the proportion of alkali hydrogen sulfide in the reaction solution, contained in the alkali sulfide as an impurity , certain proportions of alkali metal hydroxide can also be used be added. If necessary, you can also instead the alkali metal hydroxides such compounds added be the alkali hydroxides under the reaction conditions split off or form.

According to the invention, meta- and para-dihaloaromatic compounds can be used of the formula (I) or (II) can be used. The Ratio of meta- to para-dihaloaromatic compounds can be up to to be 30:70.

For the preservation of thermoplastically processable polyphenylene sulfides p-dihaloaromatic compounds are particularly preferred used.  

If branched polyarylene sulfides are to be produced, should contain at least 0.05 mol% of a tri- or tetrahaloaromatic of formula (III) can be used.

Examples of dihaloaromatic compounds to be used according to the invention of the formula (I) are: p-dichlorobenzene, p-dibromobenzene, 1-chloro-4-bromobenzene, 1,3-dichlorobenzene, 1,3-dibromobenzene and 1-chloro-3-bromobenzene. You are alone or usable in a mixture. Particularly preferred are 1,4-dichlorobenzene and / or 1,4-dibromobenzene.

Examples of dihaloaromatic compounds to be used according to the invention of the formula (II) are: 2,5-dichlorotoluene, 2,5-dichlorxylene, 1-ethyl-2,5-dichlorobenzene, 1-ethyl-2,5-dibromobenzene, 1-ethyl-2-bromo-5-chlorobenzene, 1,2,4,5-tetramethyl-3,5-dichlorobenzene, 1-cyclohexyl-2,5-dichlorobenzene, 1-phenyl-2,5-dichlorobenzene, 1-benzyl-2,5-dichlorobenzene, 1-phenyl-2,5-dibromobenzene, 1-p-tolyl-2,5-dichlorobenzene, 1-p-tolyl-2,5-dibromobenzene, 1-hexyl-2,5-dichlorobenzene, 2,4-dichlorotoluene, 2,4-dichloroxylene, 2,4-dibromocumol and 1-cyclohexyl-3,5-dichlorobenzene. They are alone or in a mixture with each other.

Examples of tri- or Tetrahaloaromatic compounds of the formula (III) are: 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,2,4-tribromobenzene, 1,3,5-trichloro-2,4,5-trimethylbenzene, 1,2,3-trichloronaphthalene, 1,2,4-trichloronaphthalene, 1,2,6-trichloronaphthalene, 1,2,3,4-tetrachloronaphthalene, 1,2,4,5-tetrachlorobenzene, 2,2'-4,4'-tetrachlorobiphenyl, 1,3,5-trichlorotriazine.  

Generally any polar solvent can be used for the reaction be used, the sufficient solubility the organic and optionally inorganic Reactants guaranteed under the reaction conditions. However, cyclic ureas are particularly preferred preferably N-alkyl lactams used.

N-alkyl lactams are those of amino acids with 3 to 11 C atoms, which may have substituents on the carbon skeleton can wear that under reaction conditions are inert.

For example, the following are used as N-alkyl lactams:
N-methylcaprolactam, N-ethylcaprolactam, N-isopropylcaprolactam, N-isobutylcaprolactam, N-propylcaprolactam, N-butylcaprolactam, N-cyclohexyl-caprolactam, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-isopropyl 2-pyrrolidone, N-isobutyl-2-pyrrolidone, N-propyl-2-pyrrolidone, N-butyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, N-methyl-3-methyl-2-pyrrolidone, N- Cyclohexyl-2-pyrrolidone, N-methyl-3-methyl-2-pyrrolidone, N-methyl-3,4,5-trimethyl-2-pyrrolidone, N-methyl-2-piperidone, N-ethyl-2-piperidone, N-isopropyl-2-piperidone, N-isobutyl-2-piperidone, N-methyl-6-methyl-2-piperidone, N-methyl-3-ethyl-2-piperidone.

Mixtures of the above solvents can also be used to get voted.

Lactams for the purposes of the present invention are lactams of amino acids with 3 to 15 carbon atoms, optionally  Can carry substituents on the carbon skeleton that are inert under reaction conditions.

Aliphatic lactams, which may also have aromatic radicals, are preferred. For example, the following lactams, optionally mixtures thereof, can be used:
Pyrrolidone- (2), (γ-butyrolactam), 5-methylpyrrolidone- (2), 5-ethylpyrrolidone- (2), piperidone- (2), (δ-valerolactam), 6-methylpiperidone- (2 ), 6-Cyclohexyl-piperidone- (2), ε-caprolactam, ω-amino-oenanthic acid lactam, ω-amino-caprylic acid lactam, ω-aminolauric acid lactam, ω-aminohexadecanoic acid lactam, 1-methyl-homopiperazinone- (5), 5 pyrrolidone- (2), 5-benzyl-pyrrolidone- (2), 5,5-dimethyl-6-methoxy-piperidone- (2).

The polyarylene sulfides produced according to the invention can be combined with others Polymers such as pigments and fillers, for example Graphite, metal powder, glass powder, quartz powder, glass fibers or carbon fibers and mixed with those for polyarylene sulfides conventional additives, for example conventional stabilizers or mold release agents.

In general, the melt flow behavior of polyarylene sulfides according to ASTM 1238-70 at 316 ° C using a 5 kg weight and measured in g / 10 minutes specified.

With high melt flow values, however, this measurement can be due to the high outflow rate of the polymer melt prepare.  

The melt viscosity η _{m of} the polymer melt (in Pa · s) was therefore determined at 306 ° C as a function of the shear stress τ (in Pa) using the Instron rotational viscometer.

In this way, the melt viscosity can be determined in a very wide range from 10 ^-1 to 10⁷ Pa · s. In the Instron rheometer, the polymer is melted between a solid plate and a rotatable cone and the torque of the cone is determined. The melt viscosity as a function of the shear stress can be calculated from the torque, the angular velocity and the equipment data. The model 3250 rheometer from Instron was used; Diameter of the cone and the plate 2 cm.

The melt viscosity is given, which at a Shear stress of τ = 10² Pa is measured.

The polyarylene sulfides produced according to the invention, preferably The p-polyarylene sulfides have immediately after isolation from the reaction mixture generally melt viscosities from 0.3 × 10³ to 5 × 10⁶ Pa · s, preferably from 1.5 × 10³ to 10⁴ Pa · s and good color properties. You can directly by extrusion, extrusion blow molding, Injection molding or other usual processing techniques processed into foils, moldings or fibers. These can be used in the usual way, e.g. B. as automotive parts, fittings, electrical parts, e.g. B. switches, electronic boards, chemical resistant and  weather-resistant parts and devices such as pump housings and pump impellers, etching bath shells, sealing rings, Parts of office machines and telecommunications equipment, as well Household appliances, valves, ball bearing parts.  

Example 1 (comparative example)

This example describes the production for comparison of polyphenylene sulfide according to US Pat. No. 3,354,129.

In an autoclave equipped with a stirrer 129 g sodium sulfide trihydrate (corresponding to 1 mol Na₂S) and 300 g of N-methyl-2-pyrrolidone combined. The mixture was purged with nitrogen and slowly up to Heated at 202 ° C. A total of 19 ml of water distill from. The mixture was then cooled down to approx. 160 ° C and 147 g p-dichlorobenzene (= 1 mol) in approx. 50 g N-methyl-2-pyrrolidone added. The reaction mixture is heated under the nitrogen pressure of 2.5 bar in 30 minutes to 245 ° C, the pressure rising to 10 bar, and maintains this temperature for 3 hours. After cooling down A gray solid is isolated at room temperature then a thorough water wash for removal the inorganic admixtures is subjected.

It is dried at 80 ° C. in vacuo and 100.3 g (93%) of poly-p-phenylene sulfide are obtained with the following characteristics:
Melt viscosity ηm = 4.5 Pa · s (at τ = 10²). Thermoplastic processing is not possible without hardening.

Example 2

In a 2 liter three-necked flask equipped with a thermometer and stirrer and column is equipped with a distillate divider under nitrogen 1110 g of N-methylcaprolactam, 323.5 g  Sodium sulfide hydrate (2.45 mol), 28.0 g 50% sodium hydroxide solution, 341.1 g 1,4-dichlorobenzene (2.32 mol) 4.21 g 1,2,4-trichlorobenzene (1 mol%, based on dichlorobenzene) and 30.2 g of N, N-dimethylacetamide (15 mol% based on Na₂S) and 4.44 g (0.035 mol) ε-caprolactam. The reaction mixture is slowly heated to boiling. From the distilling azeotrope, consisting of water and p-dichlorobenzene, water is separated off and p-dichlorobenzene returned to the reaction vessel. To There is no 2 hours in the distillate or in the swamp Water more detectable. It will be another 9 hours to Reflux heated and the product in the usual way Cases in water, acidification, electrolyte free washing with Water and drying isolated as a white fiber. The characterization takes place through the melt viscosity ηm.

ηm = 6.2 × 10³ Pa · s (at τ = 10² Pa).

Example 3

As example 2, but only with 1.68 g of 1,2,4-trichlorobenzene (0.4 mol%, based on dichlorobenzene as branching agent) ηm = 1.45 x 10³ Pa · s (at τ = 10² Pa).

Example 4

This example was based on the use of the branch 1,2,4-trichlorobenzene is dispensed with.

ηm = 3.2 × 10² Pa · s (at τ = 10² Pa).  

Example 5

As example 2, but instead of the 4.44 g ε-caprolactam 3.77 g of pyrrolidone used. It turned white PPS with a melt viscosity of the precipitated p-polyphenylene sulfide:

ηm = 5.8 x 10³ Pa · s (at τ = 10² Pa).

Example 6

As example 2, but instead of the 4.44 g of ε-caprolactam, 8.74 g of laurolactam were used. η _{m of} the p-polyphenylene sulfide obtained:

ηm = 4.2 x 10³ Pa · s (at τ = 10² Pa).

Example 7

Analogously to Example 4: 1110 g of N-methylcaprolactam, 323.5 g Sodium sulfide hydrate (2.45 mol) 2.4 g 50% sodium hydroxide solution, 341.1 g 1,4-dichlorobenzene (2.32 mol) and 38.05 g Sodium acetate (20 mol% based on Na₂S) and 4.44 g 0.035 mol) ε-caprolactam. 233.4 g of white are obtained Polyphenylene sulfide with a melt viscosity of ηm = 3.0 × 10² Pa · s (at τ = 10² Pa).

Example 8

As example 7, but with 29.4 g ε-caprolactam and Change that solutions of NMC (N-methylcaprolactam) and DCB (dichlorobenzene) and sodium sulfide hydrate, ε-caprolactam  and sodium acetate with simultaneous drainage be brought together. Melt viscosity ηm = 3.5 × 10² Pa · s (at τ = 10² Pa).

A prepared according to Example 2 of DE-OS 32 43 189 p-polyphenylene sulfide (removing the free water from the reaction, no addition of lactam) showed both a darker color before and after melting and a stronger acidic development when melting corrosive gaseous components as such p-Polyphenylene sulfides according to the invention according to Examples 7 and 8 getting produced. The melting was at 320 ° C, the acidic gases with nitrogen as a trailing gas in a wash bottle with 1 N sodium hydroxide solution transferred and the used or neutralized Sodium hydroxide solution determined by titration.

Claims (9)

1. Process for the production of high molecular weight, optionally branched polyarylene sulfides

• a) 50-100 mol% of dihaloaromatic compounds of the formula and 0-50 mol% of dihaloaromatic compounds of the formula in which
  X stands for halogen meta or para to each other and
  R¹ is the same or different and can be hydrogen, alkyl, cycloalkyl, aryl, alkylaryl, arylalkyl, where two mutually ortho radicals R¹ can be linked to form an aromatic or heterocyclic ring and always a radical R¹ is different from hydrogen and
• b) 0 to 5 mol%, based on the sum of components a) and b) of a tri- or tetrahaloaromatic of the formula ArX _n (III) where
  Ar is an aromatic or heterocyclic radical,
  X represents halogen and
  n stands for the number 3 or 4 and
• c) alkali metal sulfides, preferably sodium or potassium sulfide or a mixture thereof, preferably in the form of their hydrates or aqueous mixtures, optionally together with alkali metal hydroxides, the molar ratio of (a + b): c in the range from 0.85: 1 to 1, 15: 1 can be
• d) optionally in the presence of catalysts known to accelerate the reaction, characterized in that the reaction is carried out in a polar solvent which contains 0.5 to 100 mol%, based on the moles of dihaloaromatic, of a lactam.

2. The method according to claim 1, characterized in that that aliphatic lactams are used. 3. The method according to claim 1, characterized in that ε-caprolactam is used. 4. The method according to claim 1, characterized in that the hydrated reactants completely be dewatered and the reaction pressure-free or pressure is carried out. 5. The method according to claim 1, characterized in that in addition 1 to 100 mol%, preferably 1 to 25 mol%, based on the moles of alkali sulfide, N, N-dialkylcarboxamides are used. 6. The method according to claim 1, characterized in that the reaction via a batch or continuous mode of operation is carried out. 7. The method according to claim 1, characterized in that the reactants and the polar solvent individually or in mixtures or solutions at temperatures of 200 ° C with simultaneous drainage brought together and reacted will.   8. The method according to claim 1, characterized in that N-methyl-ε-caprolactam as a polar organic Solvent is used. 9. The method according to claim 1, characterized in that 1,2,4-richlorobenzene as a polyhaloaromatic of formula (III).